Balanced magnetic brake assembly for exercise cycling apparatus

ABSTRACT

A brake assembly for exercise cycling apparatus comprises rotor means ( 2 ) with at least one pair of magnetic elements ( 4, 4′ ) adapted to be rotated about a longitudinal axis (X) by a user who applies a driving torque thereon, stator means ( 3 ) adapted to cooperate with the at least one pair of magnetic elements ( 4, 4′ ) to generate a resistance torque adapted to oppose the above driving torque, guide means ( 7 ) associated to the rotor means ( 2 ) to cause translation of the magnet elements ( 4, 4′ ) along respective directions (d, d′) having at least one radial component to cause variation of the resistance torque proportionally to the driving torque. The magnetic elements ( 4, 4′ ) are reciprocally coupled to make the displacement thereof along directions (d, d′) mutually dependent and with substantially the same length (l, l′).

FIELD OF THE INVENTION

The present invention finds application in the field of sport and leisure accessories, and particularly relates to a balanced magnetic brake assembly for exercise cycling apparatus.

The invention further relates to an exercise cycling apparatus incorporating such assembly.

BACKGROUND OF THE INVENTION

Exercise cycling apparatus are known which essentially comprise a support frame having a bolt for locking the hub of the rear wheel of a bicycle so that the latter can rotate by contact engagement with a horizontally extending roller by applying a driving torque which is variable according to the pedaling force exerted by the user.

Such roller is braked by a brake assembly suitable to generate a resistance torque opposing the applied driving torque to simulate a more or less difficult route, thereby training the muscular and cardiovascular systems of the user. The resistance torque is typically generated by various types of means: mechanical, hydraulic, electric and/or magnetic elements.

U.S. Pat. No. 7,011,607 discloses a brake assembly of the type with magnetic elements, which comprises a disc with a plurality of permanent magnet elements mounted to corresponding helical springs in respective guide grooves, to control radial displacement thereof upon rotation of the support disc on which they are mounted.

One drawback of this prior art solution is that the disc with the magnetic elements mounted thereon tends with time to produce vibrations of variable intensity, thereby causing malfunctioning and unbalancing of the roller which, in the worst cases, may involve the mechanical collapse of the whole structure.

SUMMARY OF THE INVENTION

The object of this invention is to overcome the above drawbacks, by providing a brake assembly for a training roller that is highly efficient and relatively cost-effective.

A particular object is to provide a brake assembly of the magnetic type that is well balanced.

Another object of the invention is to provide a magnetic brake assembly that is not subjected to vibrations even after may hours of use.

These and other objects, as better explained hereafter, are fulfilled by a brake assembly for exercise cycling apparatus as defined in claim 1, comprising rotor means with at least one pair of magnetic elements adapted to be rotary driven about a longitudinal axis by a user applying a driving torque, stator means adapted to cooperate with said at least one pair of magnetic elements to generate a resistance torque adapted to counteract said driving torque and guide means associated to said rotor means to cause translation of said magnet elements along respective directions having at least one radial component to cause variation of said resistance torque proportionally to said driving torque.

According to the invention, the magnetic elements are reciprocally coupled to make displacements thereof along said guide means mutually dependent and with substantially the same length.

Thanks to this particular configuration, the brake assembly of the invention is well balanced and vibration-free unlike prior art assemblies.

As a consequence of the mutual coupling of the magnetic elements, which causes their displacements to be mutually dependent and of substantially equal length, the point of application of the moment of the resistance torque will be substantially fixed and substantially coincident with the point of application of the moment of the driving torque, thereby providing a well-balanced long-life assembly, free of vibration and part misalignment problems.

Advantageously, the magnetic elements may be reciprocally coupled by a kinematic chain, to make easier the construction of the present invention.

The term “kinematic chain” as used herein is intended to mean an assembly of mechanical elements interconnected by kinematic pairs in which each mechanical element has such a motion, relative to any other element, that its points have uniquely determined paths, thereby forming a system with only one degree of freedom.

The term “kinematic pair” as used herein is intended to indicate two mechanical parts in contact with each other, which are so interconnected to transmit motion to each other and such that one mechanical part moves relative to the other with only one degree of freedom.

Conveniently, the kinematic chain for connecting the magnetic elements may be of the closed type.

The term “closed kinematic chain” as used herein is intended to indicate a kinematic chain in which the mechanical parts at the ends are connected to each other.

Preferably, the kinematic chain may include at least one prismatic pair.

The term “prismatic pair” as used herein is intended to indicate a kinematic pair in which a mechanical part moves within another mechanical part with a rigid translational motion.

BRIEF DESCRIPTION OF DRAWINGS

Further features and advantages of the invention will be more apparent upon reading the detailed description of a preferred, non-exclusive embodiment of a brake assembly according to the invention, which is described as a non-limiting example with the help of the annexed drawings, in which:

FIG. 1 is an exploded view of the assembly of the invention;

FIG. 2 is an axonometric view of certain details of the brake assembly of FIG. 1;

FIG. 3 is an exploded view of the assembly of FIG. 2;

FIG. 4 is a bottom view of the assembly of FIG. 2, in which the disc 12 is depicted by dashed lines;

FIG. 5 is a front view of the assembly of FIG. 2, in which the magnetic elements 4 are in their start point positions;

FIG. 6 is a front view of the assembly of FIG. 2, in which the magnetic elements 4 are in their end point positions;

FIG. 7 is an axonometric view of a exercise cycling apparatus incorporating the assembly of the present invention.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

Referring to the above figures, the brake assembly of the invention, generally designated by numeral 1, will be advantageously fitted, as shown in FIG. 7, to a exercise cycling apparatus A.

The exercise apparatus comprises a support frame B for the rear wheel of a bicycle, attaching means M for securing the wheel hub to the frame B, a roller C designed to come in contact with the wheel to be rotated by a user through the application of a torque and the brake assembly 1 designed to generate a resistance torque opposing the user-applied driving torque.

As shown in FIG. 1, the assembly 1 basically comprises rotor means and stator means, generally designated with numerals 2 and 3 respectively, which are enclosed in two protective casings G and G′, which also contain the roller C.

A pair of magnetic elements 4, 4′ are associated to the rotor means 2, which include a support disc 11, and are designed to be rotated about a longitudinal axis X through the action of a user on the roller C; this latter is connected to the rotor means 2 by a control shaft 5, defining the axis X. The disc 11 is rotatably and rigidly mounted to shaft 5 to move integrally therewith.

Each of the magnetic elements 4, 4′ has two permanent magnets 9, 9′ mounted to respective magnet holding plates 10. It will be understood that the magnetic elements may include any number of magnets, permanent or not, without departure from the inventive scope as defined in the annexed claims.

The stator means 3 include a ferromagnetic disc 6 designed to cooperate with the magnetic elements to generate the resistance torque which opposes the above user-applied driving torque.

The exercise apparatus A, the support frame B, the roller C, the rotor means 2 and the stator means 3 may be configured, by way of example only and without limitation to the invention, according to the teachings of patent U.S. Pat. No. 6,761,254.

Guide means, generally designated by numeral 7, are associated to the rotor means, to allow translation of the magnetic elements along respective substantially radial directions d, d′ with opposite orientations V, V′ to cause the resistance torque to change proportionally to the driving torque.

For this purpose, the guide means 7 include a pair of arms 12, 12′ pivoted on disc 11, as shown in FIG. 1 and rigidly coupled to the magnetic elements 4, 4′ (through rigid fastening to the magnet holding plates 10) proximate to a respective longitudinal end 13, 13′ to rotate radially outwards in the direction of arrows F, F′, in response to the centrifugal force induced by the driving torque.

Thus, as the user increases the driving torque, hence the pedaling rate, he/she will encounter an increasing resistance, with apparent exercise benefits.

The magnetic elements 4, 4′ are interconnected by a closed kinematic chain, generally designated by numeral 8, so that their displacements along axes d, d′ are mutually dependent and have substantially the same length l, l′.

For this purpose, the kinematic chain 8 will include two prismatic pairs 14, 14′, composed of pins 15, 15′, each associated to a respective magnetic element 4, 4′, and sliding in respective substantially radial slots 16, 16′ formed in a substantially rigid plate 17.

The rigid plate 17 will be pivotally mounted to the shaft 5 to freely rotate about the axis X integrally with the magnetic elements 4, 4′. Due to size requirements, the slots 16, 16′ will be formed in substantially radial appendices 18, 18′ of the plate 17 which extend from a central portion 19.

Advantageously, the slots 16, 16′ extend along substantially parallel directions D, D′ which are appropriately inclined by an angle α with respect to the displacement directions d, d′ of the magnetic elements 4, 4′, to guide the circular motion of the arms 12, 12′ about fulcrum 13, 13′.

In order to counteract the centrifugal force, the guide means 7 further comprise elastic means 20, 20′, which include, in the preferred but non exclusive embodiment hereof, as shown in the figures, a pair of helical springs acting on the arms 12, 12′ to allow this latter to open in response to a predetermined value of said force.

Proper selection of the spring size will enable opening of the arms 12, 12′ and translation of the magnets 14, 14′ from a given value of the driving torque.

For this purpose, each spring 20, 20′ will have a first end 21, 21′ connected at a first point 22, 22′ at the fulcrum end 13, 13′ of the arms 12, 12′ and a second end 23, 23′ connected at a second point 24, 24′ at the opposite end 25, 25′ of the same arms 12, 12′.

Suitably, cooling means are provided, including a fan 26 associated to the plate 17 at the central portion 19.

The operation of the brake assembly 1 is shown in FIGS. 5 to 6.

FIG. 5 shows a first operating position of the assembly 1 in which the magnetic elements 4, 4′ are in the rest position, corresponding to the minimum resistance torque. As soon as the disc 11 starts to rotate at a speed ω, the centrifugal force will induce the arms 12, 12′ to rotate about the fulcrum points 13, 13′ on the direction of arrows F, F′. Due to such rotation, the magnetic elements 4, 4′ start to translate along the axes d, d′ in the directions V, V′ guided by the pins 15, 15′ in the slots 16, 16′.

FIG. 6 shows the end point of the elements 4, 4′ corresponding to the maximum resistance torque. Also, in such position, the springs 20, 20′ have the greatest elongation. Thus, the translational displacement of the magnetic elements 4, 4′ along d, d′ has a maximum length l, l′.

The above disclosure clearly shows that the assembly of the invention fulfills the intended objects and particularly meets the requirement of providing a well balanced magnetic brake assembly.

The interconnection of the magnetic elements 4, 4′, which causes their translational displacements along the directions d, d′ to be mutually dependent and have substantially the same length, provides a well balanced and long-life assembly, free of vibration and part misalignment problems.

The assembly of this invention is susceptible of a number of changes and variants, within the inventive principle disclosed in the appended claims. All the details thereof may be replaced by other technically equivalent parts, and the materials may vary depending on different needs, without departure from the scope of the invention.

While the assembly has been described with particular reference to the accompanying figures, the numerals referred to in the disclosure and claims are only used for the sake of a better intelligibility of the invention and shall not be intended to limit the claimed scope in any manner. 

1. A brake assembly for an exercise cycling apparatus, comprising: rotor means (2) with at least one pair of magnetic elements (4, 4′) designed to be rotary driven about a longitudinal axis (X) by a user exerting a driving torque thereon, stator means (3) designed to cooperate with said at least one pair of magnetic elements (4, 4′) to generate a resistance torque opposing said driving torque; guide means (7) associated to said rotor means (2), to allow translation of said magnetic elements (4, 4′) along respective directions (d, d′) having at least one radial component, to cause said resistance torque to change proportionally to said driving torque, characterized in that said magnetic elements (4, 4′) are reciprocally coupled o male their displacements along said directions (d, d′) mutually dependent and with substantially the same length (l, l′).
 2. Assembly as claimed in claim 1, characterized in that said magnetic elements (4, 4′) are reciprocally coupled by a kinematic chain (8).
 3. Assembly as claimed in claim 2, characterized in that said kinematic chain (8) is of the closed type.
 4. Assembly as claimed in claim 2, characterized in that said kinematic chain (8) comprises at least one prismatic pair (14, 14′).
 5. Assembly as claimed in claim 4, characterized in that said at least one prismatic pair (14, 14′) comprises a pair of substantially radial slots (16, 16′) formed in a substantially rigid plate (17, 17) integral with said rotor means (2), and pins (15, 15′) associated to said magnetic elements (4, 4′) slidably guided within said slots (16, 16′).
 6. Assembly as claimed in claim 5, characterized in that said plate (17) is rotatably mounted to a shaft (5) defining said longitudinal axis (X), to rotate freely about said axis (X) integrally with said magnetic elements (4, 4′).
 7. Assembly as claimed in claim 6, characterized in that said slots (16, 16′) extend along directions (D, D′) are substantially parallel to each other and inclined with respect to said translation directions (d, d′) of said magnetic elements (4, 4′).
 8. Assembly as claimed in claim 7, characterized in that said slots (16, 16′) are formed in substantially radial appendices (18, 18′) of said plate (17) which extend from a central portion (19).
 9. Assembly as claimed in claim 1, wherein said rotor means (2) include a support disc (11) which is rotatably mounted to said shaft (5) characterized in that said guide means (7) include at least one pair of arms (12, 12′) pivoted on said disc (11) and rigidly coupled to said magnetic elements (4, 4′).
 10. Assembly as claimed in claim 9, characterized in that each of said arms (12, 12′) pivots on said disk (11) at one longitudinal end (13, 13′) for rotating radially outwards in response to the centrifugal force induced by said driving torque.
 11. Assembly as claimed in claim 9, characterized in that said guide means (7) further include elastic means (20, 20′), acting on said arms (12, 12′) to counteract the centrifugal force and cause opening thereof in response to a predetermined value of such force.
 12. An exercise cycling apparatus comprising a support frame (B) for the rear wheel of a bicycle, a roller (C) designed to contact the bicycle wheel to be rotated by a user through the application of a driving torque, braking means to generate a resistance torque adapted to oppose said user-applied torque, characterized in that said braking means include a brake assembly as claimed in one or more of the preceding claims. 